This post on coral reefs originally appeared in June of 2016. It is re-posted now because a 2nd episode of bleaching is occurring for the second year in a row on Australia's Great Barrier Reef. The consequences to the reef system looks increasingly critical as sections of the reefs now appear to have died as the latest research indicates. Marine scientists continue their work to understand how best to restore the damaged reefs but still say:

"this new bleaching highlights the importance of global action on climate change. It’s vital the world acts to implement the Paris Agreement to reduce greenhouse gas emissions"

We once thought that impacts from climate change were decades away but what is happening to marine and coral ecosystems are proving that not to be the case. Time is short to implement effective changes in the direction of reducing atmospheric carbon pollution if we want to sustain healthy environments for marine and human life alike. the Editors.

Coral reefs are experiencing a major episode of bleaching this year. The impact to Australia's Great Barrier Reef (GBR) has received the most attention but coral ecosystems everywhere are struggling from a toxic combination of high water temperatures, induced by climate change, and a strong el nino. Corals are a natural symbiosis between a tiny marine animal and a single-cell plant. Bleaching causes the symbiosis to break apart turning the once vibrant reefs into ghostly skeletons with dazed reef fish and smothering algae.

The Howard Hughes Medical Institute developed a BioInteractive animation to help explain this coral symbiosis and the consequences of a bleaching event:

In one specific reef situation from Lizard Island in the far north of Queensland, the Australian Center of Excellence for Coral Reef Studies (CoralCoe) conducted surveys that showed portions of the Great Barrier Reef as being more than 60% bleached. An underwater video from the marine national park shows the extent of bleaching and the watercpollution from the bleached corals and their released algae.

What is not yet known is whether the corals will re-establish their symbiosis and the bleached reefs recover. It won't take long to tell.